I/O Programming - JAVA Programming for Engineers - page 177

actuallyread.Thismethodwaitsuntilinputdataisavailable,theendof
fileisdetected,oranexceptionisraised.Ifthearraypassedtothe
methodisnull,aNullPointerExceptionisraised.Ifthelengthofthearray
iszero,thennobytesarereadand0isreturned.Ifnobyteisavailablebe-
causethestreamisattheendoffile,thevalue-1isreturned.Thebytes
readarestoredinthearraypassedasanargument.

Thethirdvariationofread()hasthefollowingsignature

public int read(byte[] b, int o, int l)
throws IOException

Themethodreadsuptoonebyteofdatafromtheinputstream.The
dataisstoredatoffseto,inthearraybpassedinthecall.Themethodat-
temptstoreadlengthbytes,butasmallernumbermayberead,possibly
zero.Thereturnvalue,oftypeint,isthenumberofbytesactuallyread.
Thismethodwaitsuntilinputdataisavailable,endoffileisdetected,or
anexceptionisraised.

Java OutputStream class
TheOutputStreamclassofjava.ioistheabstractclassonwhichalloutput
streamsarebased.Theclasscontainsseveralmethodsassociatedwithout-
putstreams,includingmethodsforwritingdatatothestreamandforclos-
ingandflushingstreams.ThemethodsoftheOutputStreamclassare
shownin Table18-3 .

Table18-3
java.io.OutputStream

RETURNS NAME DESCRIPTION

void close() Closesthecurrentoutputstream.

void flush() Flushesthisoutputstream.This

forcesanybufferedoutputbytesto
bewritten.

void write(intb) Writesthespecifiedbytetothe

outputstream.

void write(byte[]b) Writesb.lengthbytesfromthe

specifiedbytearraytothisoutput
stream.

void write(byte[]b,

into,intl) Writeslbytesfromthespecified

bytearraystartingatoffsetoto
thisoutputstream.

OutputStreamisanabstractclass.In Table18-3 y oucanseethatthe
methodwrite()isoverloadedinthreedifferentimplementations.Twoare